AARoads Forum

National Boards => General Highway Talk => Traffic Control => Topic started by: talllguy on May 23, 2014, 10:38:53 AM

Title: SPUI Midpoint Signs
Post by: talllguy on May 23, 2014, 10:38:53 AM
I'm wondering how other states and jurisdictions are handling the middle area of SPUIs. Maryland SHA is using a diamond shaped ring of yellow flexible delineators and a wood framed sign that I've never really seen anywhere else. This sign is regularly smashed by errant drivers and so it's pretty well beaten up. Shouldn't it be yellow too?

How does your state do this?

(https://farm6.staticflickr.com/5515/14061886268_e7860f1e89_z.jpg) (https://flic.kr/p/nqAQSY)
SPUI Middle Sign (https://flic.kr/p/nqAQSY) by Elliott Plack (https://www.flickr.com/people/88483799@N00/), on Flickr
Title: Re: SPUI Midpoint Signs
Post by: jeffandnicole on May 23, 2014, 10:46:43 AM
I wonder if the island is the confusing part.  A left turn at a SPUI should be no more difficult than 2 opposing left turn lanes at a traditional intersection.
Title: Re: SPUI Midpoint Signs
Post by: agentsteel53 on May 23, 2014, 11:04:25 AM
I've never seen anything inside a SPUI - but my sample size is limited to California, Arizona, Idaho, and maybe a few other places, mostly out west.

the only time I've ever gotten confused was at night in Boise, and I had been driving for ~20 hours, the last several in horrific snow.  it was I-84 at the airport.  I can't remember what was bad about it, other than the sight lines just weren't quite making perfect sense to me.
Title: Re: SPUI Midpoint Signs
Post by: myosh_tino on May 23, 2014, 01:14:29 PM
The SPUI at CA-87 and Taylor Street has a small island in the middle of the intersection with a set of signs.  Here's that intersection in Google Maps Street View... http://goo.gl/maps/5RsxB

The SPUI at CA-237 and Maude Avenue has nothing inside the SPUI other than some painted lines... http://goo.gl/maps/iMQoa
Title: Re: SPUI Midpoint Signs
Post by: hbelkins on May 23, 2014, 01:37:35 PM
I'm pretty familiar with two of Kentucky's SPUIs -- US 60 over KY 4 in Lexington, and US 60 over KY 676/US 421 in Frankfort.

There's nothing but a painted diamond in the middle of the Lexington SPUI.

There have been a number of different signage attempts for the Frankfort SPUI since I began regularly passing through there about 25 years ago. Current Street View shows no signage, but the history panel that popped up when I looked it up on Street View shows some of the past attempts at signage. Those signs are probably gone because they kept getting knocked down.

Couldn't find a way to create a shortened link to share with the version of Google Maps that popped up when I looked it up.
Title: Re: SPUI Midpoint Signs
Post by: jakeroot on May 23, 2014, 02:38:08 PM
Neither Australia nor the UK use anything in the middle (I don't think you were looking for other countries, but oh well):

(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FAXOucm0.png&hash=7906270af60446e47821985662996781cdab53aa)
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F1Yaehgs.png&hash=6bf8286fd53c49486b7d3b2919dc44c2f8316a0e)

Title: Re: SPUI Midpoint Signs
Post by: getemngo on May 23, 2014, 03:27:42 PM
I took a look at a few in Michigan, and there's no pattern whatsoever:


None of them have any signs, though.
Title: Re: SPUI Midpoint Signs
Post by: 6a on May 23, 2014, 06:20:43 PM
The one at I-270 & Sawmill has this thing, I'm amazed people don't plow over it all day.

(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fimg.tapatalk.com%2Fd%2F14%2F05%2F24%2Frydasamy.jpg&hash=d4f0e8872ba175fd2ef2a3b7d2a61732166aa667)

I honestly don't remember anything on the one at I-71 & SR 665 but it's been awhile since I've been down there.
Title: Re: SPUI Midpoint Signs
Post by: realjd on May 23, 2014, 07:18:47 PM
Are all the MD SPUIs signed with such a ghetto wooden sign? It looks completely unprofessional.

Here in FL we don't usually sign the middle, but elsewhere (can't remember where) I've seen a raised diamond with a keep left sign.
Title: Re: SPUI Midpoint Signs
Post by: wisvishr0 on May 23, 2014, 08:30:07 PM
Quote from: realjd on May 23, 2014, 07:18:47 PM
Are all the MD SPUIs signed with such a ghetto wooden sign? It looks completely unprofessional.

This is my first real post here (I've been a long-time lurker), but I've seen that most of you are friendly and don't bite, so I might as well post a reply.

No, not all MD SPUIs are like that. This is the one near my house (at I-270 in MD and Falls Road):

https://www.google.com/maps/@39.07391,-77.164416,3a,75y,199.82h,69.98t/data=!3m4!1e1!3m2!1s5gBditUAaaopdnIN83co4w!2e0

The fact that they're using a wooden sign in that picture probably means it's temporary (or was supposed to be temporary). The setup doesn't seem to confuse drivers here in Rockville MD, without the sign.
Title: Re: SPUI Midpoint Signs
Post by: Brian556 on May 23, 2014, 08:47:35 PM
The ones I've seen in Florida only have yellow flexible delineators. Both of the SPUI intersections that I encountered there are under wide overpasses. Due to this fact, it is really hard to see the islands, even with the delineators, because it is just so dark under the bridges. This problem is significant enough that I think it would be a good idea to mark the islands with embedded LED lights.
Title: Re: SPUI Midpoint Signs
Post by: briantroutman on May 23, 2014, 09:05:33 PM
According to a few sources, the interchange between I-180 and US 15 (Market Street) in Williamsport is (or was) the first SPUI in Pennsylvania. If this is any indication, PA won't be using any islands or other "dead zone"  pavement markings at the center.

https://maps.google.com/?ll=41.238663,-76.999032&spn=0.001529,0.002516&t=m&z=19&layer=c&cbll=41.23874,-76.998935&panoid=eNs42CeIx98FvPpWAX4b-A&cbp=12,308.48,,0,0.69
Title: Re: SPUI Midpoint Signs
Post by: vdeane on May 23, 2014, 09:15:36 PM
NYSDOT Region 7 (I-781/US 11): http://goo.gl/maps/205Rj
No barrier, just signs in the road.

NYSDOT Region 1 (I-87/NY 2/NY 7): http://goo.gl/maps/GNG3l
I honestly didn't know the signs were ever there until I checked the street view.  Now there are just cones on the midpoint.  The signs must have gotten run over.
Title: Re: SPUI Midpoint Signs
Post by: tdindy88 on May 23, 2014, 09:19:34 PM
Never seen any signs or barriers in the middle of SPUIs in Indianapolis (granted there's only two of them.) Just dashed lines for the turn lanes. In fact, until today I didn't know there were such things as signs or barriers in the middle of the intersection at these interchanges.
Title: Re: SPUI Midpoint Signs
Post by: realjd on May 23, 2014, 10:29:20 PM
Quote from: wisvishr0 on May 23, 2014, 08:30:07 PM
Quote from: realjd on May 23, 2014, 07:18:47 PM
Are all the MD SPUIs signed with such a ghetto wooden sign? It looks completely unprofessional.

This is my first real post here (I've been a long-time lurker), but I've seen that most of you are friendly and don't bite, so I might as well post a reply.

No, not all MD SPUIs are like that. This is the one near my house (at I-270 in MD and Falls Road):

https://www.google.com/maps/@39.07391,-77.164416,3a,75y,199.82h,69.98t/data=!3m4!1e1!3m2!1s5gBditUAaaopdnIN83co4w!2e0

The fact that they're using a wooden sign in that picture probably means it's temporary (or was supposed to be temporary). The setup doesn't seem to confuse drivers here in Rockville MD, without the sign.


Welcome! We try to be friendly. Thanks for the pic. I like the gantry those lights are mounted on.
Title: Re: SPUI Midpoint Signs
Post by: getemngo on May 23, 2014, 10:33:48 PM
Quote from: briantroutman on May 23, 2014, 09:05:33 PM
According to a few sources, the interchange between I-180 and US 15 (Market Street) in Williamsport is (or was) the first SPUI in Pennsylvania. If this is any indication, PA won't be using any islands or other "dead zone"  pavement markings at the center.

Looks like it's not. That SPUI didn't open until October 2007. SPUI's site (http://web.archive.org/web/20041212052125/http://web.mit.edu/spui/www/spui/index.html) already listed one at US 22 & PA 66 (https://www.google.com/maps/@40.398493,-79.571411,3a,75y,172.12h,82.61t/data=!3m4!1e1!3m2!1shTR2oxeRLSDFD01WhnFy3w!2e0) in December 2004. (The other PA examples on his page are not what we think of as SPUIs - they're mostly left exits whose ramps meet at one intersection.) That one also has nothing to mark its center, so PennDOT's been consistent.
Title: Re: SPUI Midpoint Signs
Post by: lordsutch on May 23, 2014, 10:46:39 PM
Tennessee doesn't put anything in its SPUIs. Usually the most you'll see is striping for multi-lane left turns.
Title: Re: SPUI Midpoint Signs
Post by: jakeroot on May 24, 2014, 12:56:36 PM
Quote from: vdeane on May 23, 2014, 09:15:36 PM
NYSDOT Region 7 (I-781/US 11): http://goo.gl/maps/205Rj
No barrier, just signs in the road.

That seems like a terrible idea.
Title: Re: SPUI Midpoint Signs
Post by: Scott5114 on May 24, 2014, 01:20:13 PM
Neither of Oklahoma's SPUIs have a center island.
Title: Re: SPUI Midpoint Signs
Post by: jeffandnicole on May 24, 2014, 01:36:52 PM
Quote from: jake on May 24, 2014, 12:56:36 PM
Quote from: vdeane on May 23, 2014, 09:15:36 PM
NYSDOT Region 7 (I-781/US 11): http://goo.gl/maps/205Rj
No barrier, just signs in the road.

That seems like a terrible idea.

And real close to the lane lines.
Title: Re: SPUI Midpoint Signs
Post by: jakeroot on May 24, 2014, 02:02:30 PM
Quote from: jeffandnicole on May 24, 2014, 01:36:52 PM
Quote from: jake on May 24, 2014, 12:56:36 PM
Quote from: vdeane on May 23, 2014, 09:15:36 PM
NYSDOT Region 7 (I-781/US 11): http://goo.gl/maps/205Rj
No barrier, just signs in the road.

That seems like a terrible idea.

And real close to the lane lines.

Room for error: zero...point...zero.
Title: Re: SPUI Midpoint Signs
Post by: roadfro on May 24, 2014, 07:05:03 PM
Curiosity gets the better of me, especially to see whether there's a pattern... Here's every SPUI in Nevada and how it is marked in the center of the intersection.

"Under/Over" denotes whether the signal is under the freeway or over the freeway. Constructing agency is also noted.

Northern Nevada:
Title: Re: SPUI Midpoint Signs
Post by: jakeroot on May 24, 2014, 10:21:09 PM
British Columbia uses a central island with...what are those signs called? Also, this is only a half spui SPUI. Only exit ramps. Entrance ramps are literally around the corner.

(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FmZcuR25.png&hash=d878bfeba6d26e01980b8a7742de794aa5b4a8bb)
Title: Re: SPUI Midpoint Signs
Post by: Zeffy on May 24, 2014, 11:26:13 PM
Quote from: jake on May 24, 2014, 10:21:09 PM
British Columbia uses a central island with...what are those signs called?
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FmZcuR25.png&hash=d878bfeba6d26e01980b8a7742de794aa5b4a8bb)

The technical term for it is an OM-3L, but other than 'hazard stripe marker' I have no idea what you would actually call this.

For NJ, I'm almost certain that there are no SPUIs in the state.
Title: Re: SPUI Midpoint Signs
Post by: DaBigE on May 25, 2014, 12:10:16 AM
Quote from: Zeffy on May 24, 2014, 11:26:13 PM
Quote from: jake on May 24, 2014, 10:21:09 PM
British Columbia uses a central island with...what are those signs called?
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FmZcuR25.png&hash=d878bfeba6d26e01980b8a7742de794aa5b4a8bb)

The technical term for it is an OM-3L, but other than 'hazard stripe marker' I have no idea what you would actually call this.

For NJ, I'm almost certain that there are no SPUIs in the state.

I've also heard them referred to as "tiger boards" or "tiger stripes." Also "clearance stripers."
Title: Re: SPUI Midpoint Signs
Post by: jakeroot on May 25, 2014, 12:12:08 AM
Quote from: DaBigE on May 25, 2014, 12:10:16 AM
Quote from: Zeffy on May 24, 2014, 11:26:13 PM
Quote from: jake on May 24, 2014, 10:21:09 PM
British Columbia uses a central island with...what are those signs called?
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FmZcuR25.png&hash=d878bfeba6d26e01980b8a7742de794aa5b4a8bb)

The technical term for it is an OM-3L, but other than 'hazard stripe marker' I have no idea what you would actually call this.

For NJ, I'm almost certain that there are no SPUIs in the state.

I've also heard them referred to as "tiger boards" or "tiger stripes."

I find the signs rather interesting because they are part of a select group of signs that are, for the most part, international.
Title: Re: SPUI Midpoint Signs
Post by: J N Winkler on May 25, 2014, 01:39:56 AM
Quote from: Zeffy on May 24, 2014, 11:26:13 PMThe technical term for it is an OM-3L, but other than 'hazard stripe marker' I have no idea what you would actually call this.

"OM" = object marker, so I usually refer to these as "object markers," though that usage is technically an instance of synecdoche.
Title: Re: SPUI Midpoint Signs
Post by: cpzilliacus on May 25, 2014, 11:24:34 AM
Quote from: realjd on May 23, 2014, 07:18:47 PM
Are all the MD SPUIs signed with such a ghetto wooden sign?

No.

Quote from: realjd on May 23, 2014, 07:18:47 PM
It looks completely unprofessional.

They tend to get struck pretty frequently.

Quote from: realjd on May 23, 2014, 07:18:47 PM
Here in FL we don't usually sign the middle, but elsewhere (can't remember where) I've seen a raised diamond with a keep left sign.

I've seen those in at least two Maryland SPUIs. 
Title: Re: SPUI Midpoint Signs
Post by: vtk on May 25, 2014, 04:00:29 PM
Quote from: 6a on May 23, 2014, 06:20:43 PM
I honestly don't remember anything on the one at I-71 & SR 665 but it's been awhile since I've been down there.

Nothing in the middle of that one. A while after it opened, they did improve that one by adding extension lines and black contrast paint on all the markings. It had been fairly bad, as the vertical curvature of the bridge makes it nearly impossible to see where you're supposed to end up on the other side of the intersection.
Title: Re: SPUI Midpoint Signs
Post by: hbelkins on May 25, 2014, 04:58:25 PM
Kentucky calls them object markers.
Title: Re: SPUI Midpoint Signs
Post by: The High Plains Traveler on May 25, 2014, 11:41:00 PM
No islands, object markers or synecdouches (?). The SPUI at I-25 Exit 101 and U.S. 50 West/CO-47 in Pueblo CO is marked on the north-west movement with large signs reading DO NOT STOP UNDER BRIDGE. Seems there is an intersection about 500 feet to the west that, if signal synchronization fails, can cause a backup into the SPUI intersection during the green cycle for the offramp.
Title: Re: SPUI Midpoint Signs
Post by: talllguy on May 26, 2014, 11:59:20 PM
Lots of interesting replies here. Regarding the original SPUI I posted, the bridge deck is quite arched. Why, I'm not sure, but it is actually pretty impossible for a motorist to see their destination across the intersection, so that may be why they have posted the large sign. You can actually see this in the photo, note the oncoming cars are not visible.
Title: Re: SPUI Midpoint Signs
Post by: talllguy on May 27, 2014, 12:02:42 PM
Quote from: jake on May 24, 2014, 02:02:30 PM
Quote from: jeffandnicole on May 24, 2014, 01:36:52 PM
Quote from: jake on May 24, 2014, 12:56:36 PM
Quote from: vdeane on May 23, 2014, 09:15:36 PM
NYSDOT Region 7 (I-781/US 11): http://goo.gl/maps/205Rj
No barrier, just signs in the road.

That seems like a terrible idea.

And real close to the lane lines.

Room for error: zero...point...zero.

Man, that thing looks like it would get smashed all the time.
Title: Re: SPUI Midpoint Signs
Post by: jakeroot on May 27, 2014, 04:08:56 PM
Quote from: talllguy on May 27, 2014, 12:02:42 PM
Quote from: jake on May 24, 2014, 02:02:30 PM
Quote from: jeffandnicole on May 24, 2014, 01:36:52 PM
Quote from: jake on May 24, 2014, 12:56:36 PM
Quote from: vdeane on May 23, 2014, 09:15:36 PM
NYSDOT Region 7 (I-781/US 11): http://goo.gl/maps/205Rj
No barrier, just signs in the road.

That seems like a terrible idea.

And real close to the lane lines.

Room for error: zero...point...zero.

Man, that thing looks like it would get smashed all the time.

You can see the cardinal direction sign ("EAST") has been bent. Not surprising, of course. Also, the sign is leaning to one side, which I would think means it has been nudged previously.